\NeedsTeXFormat{LaTeX2e}

\def\CalendarVersion{3.2}
\def\CalendarVersionDate{2018/09/24}

\ProvidesClass{calendar}[\CalendarVersionDate
           LaTeX2e class file `calendar' v\CalendarVersion]

\typeout{'calendar' style \CalendarVersion \CalendarVersionDate.}
\typeout{Created by Evan Sultanik}
\typeout{****** Bugs/comments/suggestions/technicalities to Evan Sultanik -- evan@sultanik.com ******}

\RequirePackage{tabularx}

\def\@CALtrue{1}
\newcount\@currentdaynum
\newcounter{calendardate}
\newcount\StartingDayNumber

\def\dayheader#1#2{
  \vspace{-0.4\baselineskip}
  \begin{minipage}[t]{0.87\hsize}
    \raggedright
    \textit{#1}
  \end{minipage}
  \begin{minipage}[t]{0.1\hsize}
    \raggedleft
    \textit{#2}
  \end{minipage}
}
\def\activities#1{
  \parbox{\hsize}{\vspace*{5pt}\raggedright\scriptsize #1}\smallskip
}

\let\@colbreak=&

\def\printdayname#1{\hfil\textsc{#1}\hfil}

\newcommand{\dayname}[1]{
  \ifnum#1=1 Sunday\else
  \ifnum#1=2 Monday\else
  \ifnum#1=3 Tuesday\else
  \ifnum#1=4 Wednesday\else
  \ifnum#1=5 Thursday\else
  \ifnum#1=6 Friday\else
  \ifnum#1=7 Saturday\else
    \PackageError{calendar}{Unrecognized day number: #1!}
  \fi\fi\fi\fi\fi\fi\fi
}

\StartingDayNumber=1
\newenvironment{calendar}[1]{
  \newdimen\@calendarwidth
  \@calendarwidth=#1
  \begingroup
    \def\@calendarmode{\@CALtrue}
  \def\day##1##2{
  \if\@calendarmode\@CALtrue\else\PackageWarning{calendar}{The '\day' macro is expected to be used in the 'calendar' environment!}\fi
  \ifnum\@currentdaynum>7\global\@currentdaynum=1\fi
  \global\advance\@currentdaynum by 1
  \dayheader{##1}{\thecalendardate}\def\daysep{\vskip4pt\hrule\vskip4pt}
  \activities{##2}
  \addtocounter{calendardate}{1}
  \ifnum\@currentdaynum>7\@arraycr\hline\else&\fi
  }
\def\finishCalendar{
  \ifnum\@currentdaynum=6 &\\\hline\else
  \ifnum\@currentdaynum=5 &&\\\hline\else
  \ifnum\@currentdaynum=4 &&&\\\hline\else
  \ifnum\@currentdaynum=3 &&&&\\\hline\else
  \ifnum\@currentdaynum=2 &&&&&\\\hline\else
  \ifnum\@currentdaynum=1 &&&&&&\\\hline
  \fi\fi\fi\fi\fi\fi
}
  \def\BlankDay{
  \if\@calendarmode\@CALtrue\else\PackageWarning{calendar}{The '\calendarday' macro is expected to be used in the 'calendar' environment!}\fi
  \ifnum\@currentdaynum>7\global\@currentdaynum=1\fi
  \global\advance\@currentdaynum by 1
  \addtocounter{calendardate}{1}
  \ifnum\@currentdaynum>7\@arraycr\hline\else&\fi
  }

    \setcounter{calendardate}{1}
    \newcount\@currday
    \@currday=\StartingDayNumber
    \newcount\@numdays
    \@numdays=7
    \let\@cbreak=&
    \tabularx{\@calendarwidth}{|X|X|X|X|X|X|X|} \hline
    \ifnum\@currday>\@numdays\@currday=1\fi\printdayname{\dayname{\@currday}} \global\advance\@currday by 1 &
    \ifnum\@currday>\@numdays\@currday=1\fi\printdayname{\dayname{\@currday}} \global\advance\@currday by 1 &
    \ifnum\@currday>\@numdays\@currday=1\fi\printdayname{\dayname{\@currday}} \global\advance\@currday by 1 &
    \ifnum\@currday>\@numdays\@currday=1\fi\printdayname{\dayname{\@currday}} \global\advance\@currday by 1 &
    \ifnum\@currday>\@numdays\@currday=1\fi\printdayname{\dayname{\@currday}} \global\advance\@currday by 1 &
    \ifnum\@currday>\@numdays\@currday=1\fi\printdayname{\dayname{\@currday}} \global\advance\@currday by 1 &
    \ifnum\@currday>\@numdays\@currday=1\fi\printdayname{\dayname{\@currday}} \global\advance\@currday by 1 \\ \hline \hline
      \@currentdaynum=1
      \let\@firstline=\@CALtrue
}{
    \endtabularx
  \endgroup
}
